An Investigation into Salticid Numerosity

Presenter

Elise Descheneaux

Campus

UMass Amherst

Sponsor

Elizabeth Jakob, Department of Biology, UMass Amherst

Schedule

Session 1, 10:30 AM - 11:15 AM [Schedule by Time][Poster Grid for Time/Location]

Location

Poster Board A56, Campus Center Auditorium, Row 3 (A41-A60) [Poster Location Map]

Abstract

Many animals benefit from a sense of numerosity, the ability to assess relative numbers of items in their environments. Numerosity has been best studied in human infants and some non-human vertebrates, but little is known about the numerosity of invertebrates. To better understand invertebrate cognition, the jumping spider, or salticid, is a candidate that may provide useful insight into this phenomenon as these organisms have remarkably good vision, including a pair of high-acuity moveable eyes. We conducted two experiments using a novel eye tracker specifically designed to monitor spider gaze direction. In experiment 1, spiders were presented with images ranging from 1-6 crickets in random order to examine whether looking time is influenced by the number of objects and the order in which each stimulus was presented. In experiment 2, an expectancy violation protocol was used to test whether spiders can distinguish numbers from 1 to 6. Based on previous research, we hypothesized that looking time will increase linearly with group size, and that spiders will be able to distinguish numbers from one to three, but not four to six. Although data analysis is still in progress, our results will give us insight into the cognitive abilities of an invertebrate with a sesame-seed sized brain.

Keywords

Invertebrate cognition, Numerosity , Jumping spiders, Expectancy violation

Research Area

Animal Behaviour

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